A young, disabled girl is lost on a winter's night in Leith, unable to help herself or find her way home. Someone is combing the streets, frantically searching for her. Within hours of her disappearance, a body is washed up on Beamer Rock, a tiny island in the Forth being used as part of the foundations for the new Queensferry Bridge. No sooner has Detective Inspector Alice Rice managed to discover the identity of that body than another one is washed...